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Underground stope stability has important implications for the safety and efficiency of metal mining, especially when there are subsidence zones above. To analyze the stope stability around the subsidence area of the Hongling ore body, this paper innovatively adopts the 3Dmine–Rhino3D–FLAC3D coupled modeling numerical method to model and predict the excavation process of the stope around the Hongling subsidence area; it monitors and analyzes the displacement and stress-distribution changes in a selected stope roof, and its left-hand side and right-hand side walls. This paper realizes the separation and extraction of the special ore body and surface topographic features of the Hongling ore body; it discusses the stope stability characteristics around a subsidence area based on the real topography of the mining area and the occurrence form of the ore body. The study found that the influence of the upper collapse area on the undesired displacement of the downhole stope is mainly reflected in the roof displacement. As the stope position moves away from the collapse area, the roof displacement decreases significantly, the maximum displacement is at the center of the stope roof, and the maximum principal stress occurs at the corner of the stope. [ABSTRACT FROM AUTHOR]

laser shock forming (LSF) is a high strain rate forming process, which can significantly improve the formability of materials. Nevertheless, there is a lack of research on the microstructure evolution and improving mechanical properties of parts deformed by LSF. In this paper, pure copper sheet are formed into flat bottom parts under one- and two-shot LSF. The deformation topography, surface morphology and thickness distribution of the deformed parts are tested. The surface micro morphology of the mould can be additionally printed in the formed parts, and the sheet forming accuracy improved continuously and lower thickness thinning with the increase of the shock number. Transmission electron microscopy (TEM) showed that the microstructure on the surface of the formed specimens was composed of nanocrystalline arrays elongated in the direction of the transverse flow of the workpiece material. The dislocation density decreased and the twinned structures gradually disappeared with an increasing depth from the treated surface. More laser shocking can refine the metal material grain and improve material mechanical property of the formed part further. Eventually, the underlying improvement mechanism of mechanical properties induced by LSF-induced microstructure evolution on pure copper was systematically revealed. • The effect of laser shock number on the morphology, thickness and microhardness of the copper was investigated. • The microstructure evolution of sheet shocked by laser with shots was characterized and the evolution model was proposed. • The strengthening mechanism of the copper part formed by two-shot laser shock was analyzed. [ABSTRACT FROM AUTHOR]

This study presents a novel tube-forming method that employs a pulsed laser as a stamping tool to form a small-diameter bulged tube, which could not be easily obtained via conventional tube forming. A mechanism for the dynamic forming of a laser-induced micro-bulge was introduced, and an analytical model was developed to analyze the micro-bulging deformation induced by single laser irradiation. A finite element model was also built to simulate shock wave propagation and the dynamic progress of tube expansion. A series of validated deformation experiments were conducted. The study findings showed that the laser-induced shock wave diffused rapidly, causing the tube to expand at the shocked zone. When subjected to a one-shot laser shock, the tube underwent deformation with micro-bulging. The application of a confining layer was found to be beneficial for tube deformation. The magnitude of the tube deformation increased with the increase of laser shots. Moreover, as the laser pulse energy increased, the bulge deformation of the tube also increased. The proposed process provides an efficient alternative to form the expansion tube with a smaller diameter in the future. [Display omitted] • The conception and mechanism of laser shock tube bulging were introduced. • A model for the tube micro bulge induced by a single laser shock was developed. • A novel model was established to simulate the dynamic deformation in the tube. • The effect of the key parameters on tube bulge forming was investigated in detail. [ABSTRACT FROM AUTHOR]

A key obstacle to commercialization of solid oxide fuel cells is the sluggish oxygen reduction on the cathodes. In this work, a series of calcium-doped La 0.5- x Ca x Ba 0.5 FeO 3-δ (x = 0–0.2) are developed as highly active cathode materials and systematically evaluated their physicochemical properties. Among all the components, the La 0.35 Ca 0.15 Ba 0.5 FeO 3-δ cathode delivers the minimal polarization resistance (0.059 Ω cm2) and maximum power densities (452 mW cm−2) at 800 °C, and possesses better stability after long-term operation. Based on the analysis results of electrochemical impedance spectra and distribution of relaxation time, the adsorption process of oxygen on the La 0.35 Ca 0.15 Ba 0.5 FeO 3-δ cathode surface is proved to be the major rate-limiting step. These results suggest that La 0.35 Ca 0.15 Ba 0.5 FeO 3-δ can be used as a candidate cathode material for solid oxide fuel cells. • Ca-doped La 0.5−x Ca x Ba 0.5 FeO 3-δ powders are synthesized and characterized. • The La 0.35 Ca 0.15 Ba 0.5 FeO 3-δ cathode shows excellent ORR catalytic activity. • The lowest R p of 0.059 Ω cm2 is achieved at 800 °C. [ABSTRACT FROM AUTHOR]

In the paper, the disc sheet of 2024 aluminum alloy was shaped precisely into a flat-bottom cup by two stage laser shocking, and its microstructure evolution was studied by Scanning Electron Microscopy (SEM) and Electron Backscatter Diffraction (EBSD) in detail. The investigations show that the grains are elongated and continuously refined by continuous dynamic recrystallization during two stage laser shock sheet forming (TSLSSF). With the increase of strain of metal sheet, the transformation from low-angle grain boundaries and high dislocation densities to high-angle grain boundaries and low dislocation densities occurs, which improves the strength and plasticity of the processed material in comparison with the untreated material. The impact affects significantly the texture evolution process of aluminum alloy sheet under two stage forming. After laser shocking, the textures of the aluminum alloy sheet tend to be stabilized at the β-Fiber and a strong P texture is also formed. Due to the combined effect of grain size and dislocation density, the hardness of the second impact material increases less than that of the first impact. The research provides a reference for the application and development of laser shock forming. • The microstructure evolution of the material after laser shocks was characterized. • The proportion of low-angle grain boundaries first rises and then falls. • The ratio of dislocation density first enhances and then drops after laser shocks. • The textures of the sheet are inclined to be stabilized at β-Fiber and P component. • The hardness increase after the second impact is less than that after the first. [ABSTRACT FROM AUTHOR]

• A two-dimensional axial symmetric dynamic analysis model of laser shock metal disc sheet is established. • Finite difference method is used to explore the dynamic deformation behaviors of the laser shock forming. • The dynamic behaviors including displacement, velocity, and surface stress of sheet during the forming is investigated. • The effect of the applied laser shock wave pressure on sheet forming precision also is analyzed. Laser shock forming (LSF) is an advanced sheet forming technology. With the aid of forming die, it can realize sheet precise forming, and has extensive application prospects in aeronautic and electronics industries. In the paper, a two-dimensional axial symmetric numerical model of SUS304 stainless steel is established. Finite element method is utilized to explore the dynamic deformation behaviors of the laser-driving sheet impacted by the forming die. The results show that the node velocity of metal sheet increases in an oscillatory manner during initial stage and then it starts to bulge. After collision with die cavity bottom, the central region of metal sheet jumps up reversely, and experiences repeating damped vibration. The metal sheet gradually exhausts the obtained kinetic energy from the shock wave, and the flat sheet is finally shaped into the geometrical shape of die cavity. The sheet forming precision can be improved by way of increasing laser shock pressure. The corresponding experiments are also carried out to verify the predicted results. The applied method and gained results can provide a reference for theoretical research and parameters optimization in LSF. [ABSTRACT FROM AUTHOR]

Laser shock peening (LSP) was employed to squeeze compressive residual stress (CRS) into the curved surface of the round rod with diameter of 16 mm. The residual stress field was induced by nine laser shots irradiating at different locations along the specified path. The developing process of the residual stress field was investigated with finite element analysis, and the corresponding experiments were also carried out to validate the calculated results. Results demonstrate that multiple LSP with 50% overlapping rate can result in residual stress field with the maximum CRS varying from 155.2 MPa to 198.8 MPa along the direction of the rod axis. The peened surface appears wavy in shape and the maximum depth of plastic deformation in the curved surface is 13.41 μ m. The value of surface roughness increases from 3.87 μ m to 4.65 μ m. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to investigate the effect of laser peening (LP) on mechanical and wear properties of 304 stainless steel sheet. Design/methodology/approach: Three-dimensional morphology, micro-hardness and micro-structure of shocked samples were tested. The wear amount, wear track morphology and wear mechanism were also characterized under dry sliding wear using Al2O3 ceramics ball. Findings: The LP treatment generates deformation twins that contribute to the grain refinement and hardness increase. The wear test displays that the wear mechanism of samples is mainly abrasive wear and oxidation wear at 10 N load. While at 30 N, the delamination and adhesion areas of treated sample are reduced visibly compared to untreated ones. Originality/value: This study specifically investigates the mechanical and wear properties of 304 stainless steel after the direct action of LP on its surface, which shows an effective improvement on the wear resistance. For example, the wear loss of processed sample is reduced by 19% at 30 N, the friction coefficient decreases from 0.4714 to 0.4308 and the groove depth is reduced from 78.1 to 74.4 µm under same condition. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2024-0007/ [ABSTRACT FROM AUTHOR]

This paper presents the method to shape a deep conical cup with multi-step laser shocking forming. Finite element method was employed to simulate the process of three-step laser shocking forming (TSLSF), and the process of sheet deformation at each step was analyzed. Especially, sheet deformation behaviors including deforming velocity, strain, residual stress, and geometrical shape were discussed in detail. The sheet-forming experiments were carried out to validate the simulation results. The numerical predictions of the deformed sheet shape in each step were compared and discussed with the corresponding experimental forming values. The experimental results display that three geometrical cups have been fabricated by TSLSF. The experimental results are well accordance with the corresponding numerical predicted data, which validates the established prediction model of sheet forming. It also indicates that MSLSF is a feasible forming process when the flat sheet needs to be formed into a deep-depth workpiece. [ABSTRACT FROM AUTHOR]

Heterostructure construction and doping provide two powerful routes for manipulating charge carrier separation, electrical transport, optical response, and interface kinetics for photocatalysis. However, the literature reported synthetic methods until now were very time-consuming. In this work, a facile one-pot hydrothermal reaction route was designed to synthesize Si nanospheres @ Ti 3 + self-doped TiO2 nanosheet heterostructure with tunable Ti 3 + doping levels at different hydrothermal temperatures. It was found that the precursor Si nanospheres not only serve as supporter of TiO2 nanosheets, but also are the inducement of Ti 3 + doping. Due to the synergistic effect of Ti 3 + doping and Si/TiO2 heterojunctions, the optimal sample exhibited 6.74-fold enhancement for rhodamine B (RhB) photodegradation under Xe lamp irradiation compared with the pristine TiO2. The construction of Si/TiO2 heterojunction, as well as the introduced Ti 3 + doping and associated oxygen vacancies, extended the optical absorption of TiO2 into visible region and enhanced the separation efficiency of photogenerated electron-hole pairs, which finally resulted in improved photocatalytic performance of the Si@Ti 3 + self-doped TiO2 core–shell nanospheres. The designed hydrothermal route opens up an opportunity to the synthesis of doped hetero-photocatalysts in an efficient way. In the current study, Si nanospheres @Ti3+ self-doped TiO2 nanosheet heterostructure with tunable Ti3+ doping levels has been successfully fabricated by a facile one-pot hydrothermal method. The synergistic effect of Ti3+ doping and Si/TiO2 heterojunctions extends the optical absorption of TiO2 into the visible region and enhances the separation efficiency of photogenerated electron–hole pairs. The as-synthesized Si@Ti3+-TiO2 samples display higher photoactivity for organic pollutants degradation compared with pristine TiO2. [ABSTRACT FROM AUTHOR]

The effects of interfacial states on the temperature dependence of the magnetoresistance (MR) of Sr2FeMoO6-glass composites have been studied. X-ray diffraction analyses show that the glass is most likely located at the grain boundary without causing a change of the crystal structure of Sr2FeMoO6. The variation of the resistance with temperature and magnetic field indicates that the added glass layer has profound influence on the MR properties. At low temperature, the MR in low fields is enhanced notably because the insulating barrier for the intergranular tunneling is improved by adding the glass layer at the grain surface. However, at high temperature, the MR decreases rapidly with the increase of temperature due to, in addition to the enhancement of spin-independent hopping of electrons through the localized states, the fast decay of spin polarization at the surfaces of the grains. This decay is induced by the separation of the ferromagnetic grains with the nonmagnetic glass layer at the grain boundaries. [ABSTRACT FROM AUTHOR]

Two laser-induced shock wave pressures, 4.5 and 6.5 GPa, were applied to punch LC4CS aluminum sheet respectively, and the influence of different pressures on fracture behaviors was investigated. The code ANSYS/LS-DYNA, dynamic finite element software, was employed to investigate the sheet fracture behaviors during the punching process. The experimental results display that the punching quality manufactured by higher peak pressure of shock wave is better than that by lower one. The finite element method visualizes the punching process, including sheet deformation, cracks growth, and plug flying away. The computational analysis results reveal that the time to punch the sheet with higher peak pressure of shock wave is shorter than that with lower one, and the edge of punched hole resulted from the higher peak pressure is smoother than that from the lower one, which are consistent well with the experimental results. [ABSTRACT FROM AUTHOR]

Highlights • Stress waves propagation induced by two sided laser shot peening (TSLSP) is detailed. • Compressive residual stresses (CRS) are induced in whole thickness of treated region. • Tensile residual stresses (TRS) are found in surrounding region distributed with CRS. • RS distribution in the plate is closely related to the applied parameters in TSLSP. Abstract Two sided laser shock processing (TSLSP) has been an innovative process to impart the favorable compressive residual stresses into thin components without producing excessively detrimental deformation. In this paper, the investigations focus on the residual stresses distribution in the 7075-T7351 alloy plate with thickness of 2 mm, whose both side surfaces are subjected to shock waves with peak pressure 2 GPa induced by laser with duration 24 ns. The dynamic propagation and attenuation process of stress waves in thickness direction of the plate is also investigated, and the critical factors on residual stresses field are further discussed. The results reveal that the whole thickness section between the irradiated areas is distributed with the compressive residual stresses, while the surrounding of the region distributed with compressive residual stresses is accompanied by the tensile residual stresses. The distribution characteristic of residual stresses in the processed plate is closely related to the exact values of the applied parameters in TSLSP treatment. [ABSTRACT FROM AUTHOR]

Due to the differences in ore feeds and stacking procedures, segregated pore networks are commonly observed in industrial heap leaching operations, which strongly affect the pore-scale fluid flow and the resulting metal leaching efficiency. Three segregated models, namely, the agglomeration model or AM with intra-particle pores, the crushed ore model or COM with inter-particle pores and the mixed segregated model or MSM with both intra- and inter-particle pores, are defined in this work. The segregated pore network in the MSM consists of agglomerates and crushed particles. The models were obtained by performing micro-computed tomography scanning experiments in packed beds followed by image processing algorithms. Several fluid flow-related parameters were quantified to understand the effects of segregated pore networks on fluid flow in heap leaching. The isolated and connected pores co-exist in porous ore heaps, and the latter determines heap hydrodynamics. The number of connected pores in the AM is higher than in the COM. However, the connected pores with too small pore throats are very slow in fluid transfer by capillarity, resulting in stagnant regions in ore beds. A smaller tortuosity value was also observed in the COM, resulting in fast-flowing preferential fluid flow paths. These are unfavourable to yield uniform fluid flow distributions in industrial heaps. The results of this work suggest the prerequisites for improving fluid flow distribution in heaps, including well-organised heap construction procedures, controlling the particle size distribution and large-scale studies coupled with non-invasive imaging and flow simulations. • Agglomeration, crushed ore and mixed segregated models were extracted from micro-computed tomography images of packed beds. • Segregated pore networks in packed ore beds were quantified and analysed pertaining to heap leaching. • Interplay of intra- and inter-particle pores governs the fluid flow paths of pore networks, including non-uniform flow. • Large-scale beds with non-invasive imaging methods and simulations could solve industrial heap leaching. [ABSTRACT FROM AUTHOR]

Structural, magnetic, and electrical properties of Bi1-xPbxFeO3 (x=0, 0.1, 0.2, and 0.3) polycrystalline prepared by solid solution route were studied. The crystal structure data obtained from x-ray diffraction indicate that the solid solution Bi1-xPbxFeO3 successively transforms from rhombohedral to pseudocubic symmetry with an increase in the Pb concentration. The observed weak ferromagnetism and ferroelectricity at room temperature indicated the multiferroic nature of Pb-doped BiFeO3 compounds. The magnetoelectric coupling was estimated by the changes in the dielectric constant with an external magnetic field. It was found that the value of magnetodielectric effect have a maximum of 0.4% for Bi0.7Pb0.3FeO3 ceramic under a magnetic field of 12 kOe at room temperature. [ABSTRACT FROM AUTHOR]

Laser shock forming (LSF) is a sheet plastic forming technology, which employs laser-induced shock waves to make sheet metal duplicate a desired shape of the mold. In this paper, a finite element analysis (FEA) model was developed to simulate dynamic forming process with the commercial finite element code ABAQUS/Explicit, and a series of dynamic deformation behaviors of the metal sheet shaped into conical cup at the end of different periods of time were displayed and discussed in detail. The springback of conical cup and the distribution of residual stress were analyzed with ABAQUS/Standard. All these investigations could provide insight into the physics process of the ultra-fast deformation. The LSF experiment was further conducted to verify the results predicted by FEA. The experiment results are well consistent with the numerical predicted data, which validates the FEA model. It indicates that FEA can be used to simulate the forming process and optimize its parameters. [ABSTRACT FROM AUTHOR]

Bi 0.95 La 0.05 Fe 0.8 M 0.2 O 3 (M = Cr, Co, Al) ceramics have been prepared by high pressure synthesis and their structure, magnetic, thermal, and optical properties have been investigated. X-ray diffraction suggests the pure phase formation with rhombohedral structure in all samples. The structural distortion induced by dopants is further analyzed by Raman spectra. The SEM investigation reveals that Cr and Al substitution does not affect the morphologies of Bi 0.95 La 0.05 FeO 3 ceramics, while Co substitution significantly reduces the grain sizes and uniforms the morphology. The effect of substitution on the magnetic properties of Bi 0.95 La 0.05 FeO 3 is different depending on M due to different mechanisms. More interestingly, Co substitution induces a change in the spin structure from a cycloidal space modulated spin structure to a collinear G-type antiferromagnetic structure, which results in obviously enhanced magnetization at room temperature. Optical studies show a sharp absorption in the visible region for all samples. The band gap values of Bi 0.95 La 0.05 FeO 3 and Bi 0.95 La 0.05 Fe 0.8 M 0.2 O 3 ceramics with M = Cr, Co, and Al are estimated to be 2.30, 2.06, 2.12 and 2.27 eV, respectively. [ABSTRACT FROM AUTHOR]

Single-phase Bi 0.95 La 0.05 Fe 1- x Co x O 3 ceramics with x =0, 0.1, and 0.2 were prepared by high pressure synthesis. X-ray diffraction patterns demonstrated rhombohedral structure for all samples. Ferroelectric transition temperature was found to decrease with increasing cobalt content. La and Co co-doping favors weak ferromagnetism ordering with evident magnetic hysteresis loop and enhances magnetization values at room temperature, which is attributed to the change in the spin structure from a cycloidal space modulated spin structure to a collinear G-type antiferromagnetic structure. Optical properties of the samples, as studied by diffuse reflectance spectroscopy, showed low optical band gap that decreases with increasing cobalt content, which provides potential applications in photocatalytic activity and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Two sided laser shock processing (TSLSP) is often employed to improve the surface quality of thin section components, which can reduce excessive plastic deformation induced by one sided laser shock processing. Residual stresses (RS) field induced in a thin Ti–6Al–4V alloy plate by TSLSP was investigated through numerical simulation and experiments. The effects of key parameters, viz., metal plate thickness, shock wave pressure and number of laser shocks, on RS field were analyzed. The simulation results show that the RS field induced by TSLSP was distributed symmetrically in the metal plate. For thin sections, compressive residual stresses (CRS) were found to exist on the surface of both the sides and also in the mid-plane region, whereas, for thick sections, CRS were found to only distribute on the surface of both the sides. The multiple TSLSP impacts and the increasing laser shock pressure were found to have significant effects on the RS field. The RS values predicted by the model correlated well with the experimental data. [ABSTRACT FROM AUTHOR]

Laser shock forming (LSF) employs laser shock wave to form metal sheet, which is similar to explosive forming. Finite element method (FEM) is an effective method to better understand mechanism of LSF and select appropriate parameters to shape metal sheet accurately with LSF. In this paper, FEM analysis model is developed to simulate LSF, which includes how to determine the pressure loading, material constitutive model, and solution time. The commercial code LS-DYNA is applied to simulation. A sequence of dynamic deformation behaviors of metal sheet at the end of different periods are presented and discussed in detail, and the peculiar phenomena in dynamic deformation processing are discovered, which do not appear in the traditional forming processing. The final static deformation and residual stress are also predicted. The predicted results are accordance with the experimental data. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new compound based on the solid solution of BiFeO3–GdCrO3 were synthesized. [•] The structure–property relationship of the system was studied. [•] Enhanced multiferroic properties were obtained in 0.9BiFeO3–0.1GdCrO3. [•] The present materials allow us to further develop multiferroic components of BiFeO3. [ABSTRACT FROM AUTHOR]

In this paper, the failure mechanism of the absorption film (AF) subjected to double-sided laser shock processing (DSLSP) was investigated. The propagation of laser-induced stress wave in the multilayer material and the deformation process of the AF were analyzed with finite element method, and the corresponding experiments were carried out to verify the calculated results. The three-dimensional topographies of the shocked AF and the substrate were measured, and scanning electron microscope (SEM) was also used to observe the irradiated surface. The investigations show that the transmission and reflection of stress waves in the multilayer material produce outward stretching effect on the AF, which attempts to divorce the AF from the substrate. The AF bulges from the substrate with damped oscillation if the intensity of divorced stress wave exceeds the adhesion strength between them, and the shallow depressed crater is also left on the surface of substrate simultaneously. If the multiple DSLSP proceeds on the bulged AF, it ruptures and loses the protection to the substrate. • The process of film bulge induced by double-sided laser shock process (DSLSP) is shown. • The propagation of stress waves at the Al-Cu interface are discussed. • The failure mechanism of the absorption film subjected to DSLSP is investigated in detail. [ABSTRACT FROM AUTHOR]

Highlights: [•] A green route is developed for synthesis of water-soluble and fluorescent Fe:ZnSe quantum dots. [•] Tunable luminescence intensity can be realized with different ligand-to-Zn molar ratios. [•] The obtained quantum dots are in the so-called “quantum confinement regime”. [Copyright &y& Elsevier]

[Display omitted] • The cup with large area bottom can be formed with nine-spot laser shock in sequence. • The different order of laser shocking can not change the final forming accuracy. • An appropriate pressure of laser shock wave must be adopted in sheet shock forming. • The forming accuracy rises with the raise of laser spot covering ratio within a threshold. The paper presents a large-bottom cup formed by multiple-spot laser shocking. A 3D finite element model was developed with computational hardware and software resources to simulate the shape evolution process of cup manufactured by gradual-increasing-shot laser shocking along a specified path. A series of intermediate cups were fabricated correspondingly to verify the predicted results. The effect of key processes, such as impact order, imposed pressure of shock wave and the covering ratio of laser shocking spot, on the final geometric shape of formed cup was also investigated and analyzed. The results of numerical simulation and experiment show that small deformation induced by each single-spot shocking is gradually accumulated to larger deformation, and multiple-spot laser shocking can form the large conic cup well. The sheet forming precision is not affected by the order of laser shocking, but is seriously decreased by the improper pressure of imposed shock wave. When the covering ratio of laser shocking exceeds threshold value, sheet forming precision is not changed any more even if the covering ratio increases. In general, the multiple-spot laser shocking forming is a technology of sheet incremental forming, and it can enlarge greatly the scope of sheet forming with laser shocking. [ABSTRACT FROM AUTHOR]

Abstract: A method for the large-scale synthesis of water-soluble Fe:ZnSe nanocrystals was developed, which manipulates the optical properties by controlling the reaction temperature. The Fe:ZnSe nanocrystals crystallize well, and possess cubic zinc blende structure, and the obvious broadening of the diffraction peaks is attributed to their small size nature. The formation of mercaptoacetic acid capped Fe:ZnSe nanocrystals was confirmed by FT-IR analysis. The emission peaks of the resulting nanocrystals can be tuned from 419nm to 453nm, and the absorption edges of the obtained nanocrystals are blue-shifted compared with the corresponding band gap of bulk ZnSe due to the quantum confinement effect. Finally, the Fe:ZnSe nanocrystals yield in a single reaction was determined to be 2.88g. [Copyright &y& Elsevier]

Abstract: Single-phase Bi0.85La0.1Ho0.05FeO3 multiferroic ceramics were prepared by a rapid liquid sintering method. The ceramics exhibited an obvious ferroelectric loop with a remnant polarization of 11.2μC/cm2 and also showed weak ferromagnetism with the remnant magnetization of 0.179emu/g at room temperature. A considerable enhancement of the polarization on magnetic poling and a dielectric anomaly in the vicinity of the antiferromagnetic transition temperature due to the intrinsic magnetoelectric coupling effect were observed in Bi0.85La0.1Ho0.05FeO3 ceramics. The dielectric constant for the Bi0.8La0.1Ho0.05FeO3 samples at room temperature decreases with increasing applied magnetic fields, and the coupling coefficient (ɛ′(H)− ɛ′(0))/ɛ′(0) reaches −1.04% at H =10kOe. [Copyright &y& Elsevier]

Abstract: Single-phase Bi1−x Eu x FeO3 (0≤ x ≤0.3) multiferroic ceramics were prepared to study the effects of Eu substitution on their crystal structure and ferroelectromagnetic behavior. X-ray diffraction studies revealed a sequence of the composition-driven structural phase transitions R3c→ Pn21 a (occurs at x =0.2). Magnetic measurements revealed that Eu substitution can effectively induce the appearance of the spontaneous magnetization, which was significantly enhanced upon the composition-driven transition from a rhombohedral to an orthorhombic phase. The leakage current was found to be reduced on increased Eu concentration. The electric hysteresis loops were obtained in the Bi1−x Eu x FeO3 ceramics, but the loops were not really saturated. The magnetoelectric coupling in Eu-doped BiFeO3 was estimated by the changes in the dielectric constant with an external magnetic filed. [Copyright &y& Elsevier]

The paper presents a surface-based approach for geometric feature recognition for the purpose of automating the process planning of freeform surface machining. The proposed approach consists of the following four steps for recognition of the geometric features: conversion and preprocessing of the surface geometry data, subdivision of NURBS surface, reconstruction of surface orientation areas, and recognition of geometric features. The proposed scheme assumes that the input geometry data form is based on an IGES CAD model and the surface model can be represented in the form of trimmed NURBS surfaces. The connectivity relations of the product surfaces are analyzed and each surface is subdivided into orientation regions based on the surface normal vector over a certain point density grid, and then all the connected regions with the same orientation type are grouped into surface orientation areas. After that, the geometric feature will be recognized through the analysis of area connectivity and relationship. The paper describes the developed algorithms on surface orientation region subdivision, surface orientation area reconstruction, and geometric feature recognition. The verified feasibility study of the developed method is also presented. [Copyright &y& Elsevier]

Based on Z-map method, in this paper the development of a geometric model for the linear motor equipped EDM die-sinking process is described. Firstly discussed are the advantages and benefits of the introduction of the linear motor into EDM die-sinker. The current model has been employed to calculate the minimum gap distance for sparks to occur and to analyze the possibility of spark generation between the workpiece and electrode surfaces. Also calculated is the crater formed by a single spark. The final machined surface topography is predicted. The influence of peak current and discharge duration on the average surface roughness is simulated. The experiment has been conducted to study the effects of machining conditions as well as to verify the effectiveness of the developed geometric model. [Copyright &y& Elsevier]

As one of key cleaner production methods, heap bioleaching of copper relies on leaching solution to extract valuable copper ions from agglomerations, crushed ores, waste rocks of low-grade copper sulfides, which is a complex reaction system with the existence of thermal-hydraulic-mechanical-chemical-biological (THMCB) multi-physics field and multi-phase (gas-solid-liquid) coupling. In this porous bio-heap, the reactive fluid flow (RFF), regarded as the pivotal media of heat transfer, ionic exchange, and microbial proliferation, is heavily affected by THMCB coupling, therefore influencing the bioleaching efficiency. Further, the undesirable lower leaching efficiency and heavy metallic ions pollution commonly appeared due to misunderstanding and out-of-control of RFF. The systematic and overall reviews focusing on REF RFF and THMCB are still lacking and urgently needed. This review scrutinized the current research landscape in understanding the RFF behavior and its interacted responses to THMCB coupling. It specifically focused on visualization of the RFF using macro-/meso-/micro-scale undisturbed detection. In addition, the description of RFF via mathematical model and 3D/2D simulation was summarized, and the intervention of RFF using THMCB amelioration and controlling was critically reviewed. This paper provides insights into the RFF in porous reaction systems and guidance to efficient industrial heap operations theoretically. • Reactive fluid flow (RFF) in bio-heap leaching is systemically reviewed. • Potential Effect of thermal-hydraulic-mechanical-chemical-biological (THMCB) coupling on RFF is firstly discussed. • Detection methods of RFF at the macro-/meso-/micro-scale are summarized. • Hydrodynamic modeling of RFF in bio-heaps is well compared. • Targeted intervention of RFF and its influence on bio-heaps operation is analyzed. [ABSTRACT FROM AUTHOR]

Aluminum (Al) fluoropolymer composites are widely used in the field of energetic materials. At present, it is a research hotspot to improve the agglomeration of nano-aluminum powder in fluoropolymer and make micro-nano-Al/fluorine rubber (F2601) composites. In this study, it was the first step to modify the surface of nano-aluminum (n-Al) powders, and then Al/F2601 composite microspheres were prepared by Pickering emulsion. The effects of oil–water ratio, solid content and fluorine–aluminum ratio on the stability of the emulsion were investigated. Al/F2601 microspheres with particle sizes of about ≤ 50 μm and different surface pores were prepared by controlling various conditions, which appeared the thermal decomposition peak between 485.5 °C and 524.9 °C. The combustion process of samples in the air was recorded by a high-speed camera, the composites with different F2601 contents burn stably and show a clear pattern of combustion velocity, and the maximum linear combustion velocity is up to 30.7 cm s−1. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to investigate the dynamic forming process of the micro dent fabricated by laser shock processing on 2024-T3 aluminum alloy. The effect of laser pluse energy on the deformation of micro dent was also discussed in detail. Design/methodology/approach: It uses finite element analysis method and the corresponding laser shocking experiment. Findings: The results demonstrate that the dynamic formation process of micro dent lasts longer in comparison with the shock wave loading time, and the depths of micro dents increase with the increasing laser energy. In addition, laser shocking with higher energy can result in more obvious pileup occurred at the outer edge of micro dent. Originality/value: Surface micro dents can serve as fluid reservoirs and traps of the wear debris, which can decrease the effects of the wear and friction in rolling and sliding interfaces. The investigations can not only be propitious to comprehensively understand the forming mechanism of laser-shocked dent, but also be beneficial to get sight into the residual stress field induced by laser shocking. [ABSTRACT FROM AUTHOR]

In laser shock processing, overlays are used to enhance peak pressures and prolong pulse widths of laser shock waves. The overlay usually has three types: rigid, flexible, and liquid overlays. In this paper, some mathematical models are constructed to analyze the process of laser-induced shock waves and pressure attenuations of the shock waves. The analyses indicate that the peak pressure of shock waves depends on the deformation amount of the overlays and the pressure attenuations depend on the deformation speed of the overlays, while the deformation amount and deformation speed are determined by the density and thickness of the overlays. Besides, for the rigid overlay, the elastic modulus must be taken into account in addition to its density and thickness. Furthermore, the reflected waves from the overlays enhance the shocking effects of laser-induced shock waves. Therefore, the rigid overlays are superior to the flexible and liquid overlays. [ABSTRACT FROM AUTHOR]

Advanced techniques, such as 3D printing, have been developed for the design and fabrication of unique structures to meet user-customized requirements. However, the traditional 3D printing technique has not been used for the construction of the nanothermite hollow structure, hindering the development of 3D printing and the further applications of nanothermite materials. Recently, we discovered an unexpected self-accelerating combustion phenomenon of hollow fiber nanothermite (Al/CuO/fluororubber ternary composite). The results show that the stable flame propagation rate of the nanothermite hollow fiber significantly improved compared to the solid fiber from 0.09 to 395 m/s (up to 4400 times higher than the solid fiber), and the combustion test also exhibits the self-accelerating propagation of combustion by the "cavity-mediated effect." With the versatile shape-design capability, this work on hollow structure nanothermite and developmental potential of 3D printing could lead to structural applications of microrockets, aerospace propulsion components, space exploration, microelectromechanical system (MEMS) devices, and high temperature destruction of MEMS. [ABSTRACT FROM AUTHOR]

Abstract Perovskite-type LaCoO 3 thin films were deposited on (001) oriented LaSrAlO 4 , LaAlO 3 , (LaAlO 3) 0.3 (Sr 2 AlTaO 6) 0.7 and SrTiO 3 single-crystal substrates, respectively. All the films are epitaxially grown on these substrates with tetragonal distortion of CoO 6 octahedrons. Due to different lattice mismatch between the film and substrate, there exists Jahn-Teller-like tetragonal distortion with out-of-plane elongated CoO 6 octahedrons for LaCoO 3 on LaSrAlO 4 or LaAlO 3 substrate, but compressed octahedrons for LaCoO 3 on (LaAlO 3) 0.3 (Sr 2 AlTaO 6) 0.7 or SrTiO 3. All the LaCoO 3 epitaxial films, with strain-induced larger unit-cell sizes and longer Co O bond lengths compared with those of bulk LaCoO 3 , exhibit obvious visible-light-driven photocatalytic activity. The photocatalytic ability increases gradually for the LaCoO 3 grown on (LaAlO 3) 0.3 (Sr 2 AlTaO 6) 0.7 , SrTiO 3 , LaAlO 3 and LaSrAlO 4 , consistent with the increasing order of tetragonal distortion degree for CoO 6 octahedrons. It reveals that the photocatalytic performance of the LaCoO 3 films is closely related to the stain-induce tetragonal distortion of CoO 6 octahedrons. Larger degree of tetragonal distortion can further reduce the crystal field splitting energy of CoO 6 octahedrons as well as the band gap, thus enhancing the visible-light-driven photocatalytic ability of LaCoO 3. The present study demonstrates that epitaxial strain is an efficient way to controllably tune the structural distortion, electronic structure, and thereby improve the photocatalytic properties of perovskite and perovskite-derived oxides. Graphical abstract Image 1 Highlights • Octahedral distortion and photocatalysis of LCO can be tuned by epitaxial strain. • Larger tetragonal distortion can further reduce the Δ CF of [CoO 6 ] and the band gap. • The photocatalytic ability of LCO is closely related to the CoO 6 JT-like distortion. [ABSTRACT FROM AUTHOR]

Low-alkali borosilicate glass was used as the immobilization substrate, and Ce was used to replicate the trivalent and tetravalent actinides, in order to create simulated waste glass through melt heat treatment. The valence of Ce and solubility of CeO2 in waste glass were studied as well as its network structure and thermal and chemical stability. The solubility of Ce in waste glass was examined by XRD and SEM. The network structure was examined by Raman spectroscopy. The valence of Ce was determined by X-ray photoelectron spectroscopy. Thermal analysis and product consistency (PCT) were employed to determine the thermal and chemical stability of waste glasses. The results show that the solubility of cerium in low-alkali borosilicate glasses is at least 25.wt.% and precipitates a spherical CeO2 crystalline phase when it exceeds the solid solution limit; Ce is immobilized in the glass by entering the interstices of the glass network. Depolymerization and the transition from [BO3] to [BO4] occurs when CeO2 doping levels rise. About 60 percent of Ce4+ is converted to Ce3+, and the thermal stability of glass rises then falls with the increase of CeO2. All samples exhibit strong leaching resistance, with the average mass loss of Ce at 28 days being less than 10−4 gm−2d−1. [ABSTRACT FROM AUTHOR]

In this work, LaNiO 3 epitaxial thin films on (001) single-crystal LaAlO 3 and SrTiO 3 substrates were deposited by polymer assisted deposition method, respectively. Additionally, LaNiO 3 polycrystalline film was coated on ceramic substrate using LaNiO 3 powder obtained from precursor solution in polymer assisted deposition. Due to the difference of lattice mismatch between LaNiO 3 and single-crystal substrates, LaNiO 3 thin films suffer different epitaxial strain, resulting in distortion of NiO 6 octahedrons which increases with the intensity of strain. Such phenomena lead to the decrease of the field splitting energy of NiO 6 octahedron and the band gap value of LaNiO 3 , further increasing the charge transition and enhancing the visible-light photoconductivity. The existence of epitaxial strain brings more Ni2+ and adsorbed oxygen into perovskite type LaNiO 3 , introduces more oxygen vacancy defects, reduces the complex rate of photo induced electron-hole pairs, and thereby improves the photoelectric activity of LaNiO 3. This work provides a feasible method to control the structure distortion and photoconductivity effect of all-inorganic perovskite. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel manganese hexacyanoferrate/multi-walled carbon nanotubes (MnHCF/MWCNTs) nanocomposite was fabricated by mild chemical precipitation method at room temperature and further investigated as electrode materials for supercapacitors. The physical properties of as-fabricated materials were characterized by XRD, FTIR and FE-SEM techniques. Integrating these nanostructures resulted in a strong synergistic effect between the two materials, consequently leading to robust and superior composite materials with higher capacity compared with pure MnHCF and MWCNTs. Specific capacities of 370.4, 200.1 and 45.8 C g −1 were acquired for MnHCF/MWCNTs nanocomposite, MnHCF and MWCNTs, respectively. Most importantly, as-fabricated MnHCF/MWCNTs nanocomposite exhibited favorable rate capability (370.4 C g −1 and 270.6 C g −1 at 1.0 A g −1 and 6.0 A g −1 , respectively) and excellent cycling stability (87.4% capacitance retention after 2000 cycles at 1.0 A g −1 ). The simple synthesis and excellent electrochemical properties made as-fabricated nanocomposite an attractive candidate in the fields of supercapacitors and new emerging areas. [ABSTRACT FROM AUTHOR]

A novel poly(bromocresol green) (PBG)/carbon quantum dots (CQDs) composite based sensor was successfully fabricated on glassy carbon electrode by electropolymerization. As-prepared PBG/CQDs modified electrode was successfully applied in the simultaneous determination of guanine and adenine. Electrochemical responses of as-prepared modified electrode were evaluated by cyclic voltammetry and differential pulse voltammetry. Owing to the synergistic effect of PBG and CQDs, the oxidation peaks of both guanine and adenine well separated from each other and the peak potential separation was large up to 310 mV. The current of the oxidation peaks showed a linear dependence on the concentrations of guanine and adenine in the range of 0.50–142 and 0.30–130 μM with detection limits of 0.016 and 0.026 μM (S/N = 3), respectively. Moreover, as-prepared PBG/CQDs modified electrode exhibited favorable selectivity, stability and reproducibility, which had promising application for the simultaneous determination of guanine and adenine. [ABSTRACT FROM AUTHOR]

Annulus pressure control is critical to well safety in deepwater oil and gas wells, and it is crucial for deepwater high-pressure oil and gas wells, which are related to production safety. At present, the deepwater annular pressure analysis model is mainly based on the trapped annulus principle. For the high annular pressure of deepwater high-pressure oil and gas wells, it brings great management and control challenges. This paper proposes a deepwater high-pressure oil and gas well annular pressure analysis method considering formation connectivity. According to the existing measures of annular pressure management and control, the differences between various types of annular pressure management and control technology are systematically analyzed and expounded, and the annular pressure management and control technology of deepwater high-pressure oil and gas wells is proposed accordingly. At the same time, combined with the actual case of a deepwater high-pressure well in the South China Sea, the annular pressure considering different influencing factors is analyzed, and the appropriate management and control methods of annular pressure are recommended. This paper systematically summarizes and studies the analysis and control technology of annular pressure in deepwater high-pressure oil and gas wells, which provides a technical basis for China's deep water to move from conventional deepwater to deepwater high-pressure, and can provide a reference for the management and control of annular pressure in oil and gas wells in subsequent deepwater projects. [ABSTRACT FROM AUTHOR]

Water-based polyurethane paint is widely used for wood furniture by virtue of the eco-friendliness, rich gloss, and flexible tailorability of its mechanical properties. However, its low solution (water or alcohol) resistance and poor hardness and wear resistance limit its application. The emerging graphene oxide has a high specific surface area and abundant functional groups with excellent mechanical properties, endowing it with great potential to modify waterborne polyurethane as a nanofiller. In this study, graphene oxide prepared by Hummers' method is introduced in the chemosynthetic waterborne polyurethane through physical blending. The testing results demonstrate that the appropriate usage of graphene oxide at 0.1 wt% could obviously improve water absorption resistance and alcohol resistance, significantly enhancing the mechanical properties of waterborne polyurethane paint. The corresponding tensile strength, abrasion resistance, and pendulum hardness of the graphene oxide-modified paint film increase by 62.23%, 14.76%, and 12.7%, respectively, compared with the pristine paint film. Meanwhile, the composite paint film containing graphene oxide possesses superiority, including gloss, abrasion resistance, pendulum hardness, and tensile strength in contrast with the commercial paint. The use of graphene oxide to enhance the waterborne polyurethane possesses strong operability and practical value, and could provide useful reference for the modification of waterborne wood paint. [ABSTRACT FROM AUTHOR]

In this paper, the effect of doping phosphorus in a borosilicate glass matrix to improve the solubility of Mo was investigated by X-ray diffraction (XRD), Raman, and solid-state nuclear magnetic resonance (NMR) spectroscopy, and the effectiveness of Na content on P species inhibiting the growth of the crystallization of Mo was assessed. The results indicate that phosphate-doped borosilicate glass can host 4 mol% of Mo, and that such a borosilicate glass matrix could only accommodate 1 mol% of Mo without phosphate doping. The effectiveness of phosphorus may be correlated with the Na content in borosilicate glass, and a high Na content borosilicate glass matrix requires more P doping to accommodate Mo. In addition, incorporating large amounts of P can compromise the aqueous durability of the glass matrix. [ABSTRACT FROM AUTHOR]

The effects of Co doping on the structure, magnetic and the ferroelectric properties of BiFeO 3 were predicted through ab initio calculation based on density functional theory (DFT), in conjunction with experimental verification. The calculated structure of BiFe 0.83 Co 0.17 O 3 belongs to rhombohedral R 3 c , which matched well with that obtained experimentally. The calculations revealed that the magnetic properties of BiFeO 3 can be enhanced significantly by Co-doping at B-site, and the net magnetic moment of unit cell was evaluated to be 0.93 μ B for BiFe 0.83 Co 0.17 O 3 . The enhanced magnetic moments should be ascribed to the superexchange interaction of Fe 3+ –O 2− –Co 3+ . By using the Berry-phase method, the ferroelectric polarization was calculated to be 108 μC/cm 2 , which is larger than that in pure BiFeO 3 (93 μC/cm 2 ). The observed weak ferromagnetism and ferroelectric nature at room temperature indicates the multiferroic nature of BiFe 0.8 Co 0.2 O 3 sample, whose magnetoelectric coupling was verified to be 4.82% in BiFe 0.8 Co 0.2 O 3 estimated by the change of dielectric constant with external magnetic field. These results may shed some light on the controlling and tuning of the multiferroic properties of BiFeO 3 . [ABSTRACT FROM AUTHOR]

The hard particles in particle-reinforced aluminum matrix composites significantly increases tool wear during friction stir welding (FSW), resulting in the shortage of tool life. In this study, SiCp/Al composites are used as the research object, and the tool wear experiment in friction stir welding is carried out by using high-speed steel pin and high-speed steel + AlCrN coated pin. A new method for calculating tool wear based on hydrodynamic pressure is proposed, and the tool pin wear prediction model is established and verified by experiments. The results show that the wear rate of AlCrN coated pin is very low at the beginning, indicating that AlCrN coating can extend the tool life to a certain extent. However, the wear rate of the tool will increase significantly after the coating is worn away. Through the analysis of the surface wear morphology of the pin, it is found that the main mechanisms of tool wear in the friction stir welding of SiCp/Al composites are the micro ploughing and micro cutting of SiC particles. • A wear model is established for cylindrical pin during FSW of SiCp/Al composites. • Micro ploughing and Micro cutting are primary wear mechanisms for pin. • The wear characteristics of uncoated pin and AlCrN coated pin are investigated. [ABSTRACT FROM AUTHOR]

All-inorganic perovskite has aroused extensive attention as the light absorption layer of solar cells due to the high photoelectric conversion efficiency and chemical stability. In this work, RMnO 3 (RMO, R = La, Pr and Nd)/(001) LaAlO 3 (LAO) epitaxial films were prepared by the polymer assisted deposition method. All of the RMO films were grown epitaxially with tetragonal distortion (like Jahn-Taller distortion) of MnO 6 octahedron. Owing to lattice mismatch between RMO and LAO, the tetragonal distortion of MnO 6 octahedron increases when the radius of trivalent R ions increases. This reduces the crystal field splitting energy of MnO 6 octahedron, resulting in a reduction in the band gap and enhancement of the visible-light photoelectric performance. It also reveals that the surface-adsorbed oxygen plays a crucial role in the photoelectric process of the RMO epitaxial films. More surface-adsorbed oxygen, existing in RMO films with larger R ions, can enhance the double exchange of electrons in Mn3+ - O2− - Mn4+, thus preventing the recombination of photogenerated electron-hole pair and improving the photoelectric performance. These results provide a channel to tune the structure and photoelectric performance of perovskite manganese oxide. [ABSTRACT FROM AUTHOR]

Semiconductor nanocrystals have been the focus of great interest in recent years due to their size dependent physical and chemical properties. Here, we present a facile, eco-friendly and feasible approach for the fabrication of highly luminescent Fe:ZnSe nanocrystals by using low-cost, and environmentally friendly reagents and solvents, benefiting the practical applications. The developed process produces Fe:ZnSe nanocrystals having in situ capping of mercaptoacetic acid on the surface, resulting in good water solubility due to effective surface functionalization. Surface investigation of the nanocrystals indicates that mercaptoacetic acid is chemisorbed onto the surface of Fe:ZnSe nanocrystals and the sulfur atom in the thiol is coordinated to the zinc atom, leading to the formation of the covalent Zn–S bond. Ultra-small Fe:ZnSe nanocrystals were produced with average particles size ca. 4 nm, indicating they are in the alleged quantum confinement regime. The Fe:ZnSe samples are found to be nanocrystalline in nature with cubic zinc blende structure. The Fe:ZnSe nanocrystals are quasi-spherical shaped, and the regular behavior of the lattice fringes inside the nanocrystal further demonstrates that most nanoparticles have a good crystalline characteristics with no obvious defects. The microstructural properties of the Fe:ZnSe nanocrystals were probed by X-ray diffraction in detail. The photoluminescence spectrum band is relatively narrow and symmetric, which reveals the obtained Fe:ZnSe nanocrystals are nearly monodisperse and homogeneous. The photoluminescence quantum yield of the fabricated Fe:ZnSe nanocrystals was calculated to be ca. 35%, that makes Fe:ZnSe nanocrystals a promising candidate for applications in biolabeling, bioimaging, and light emitting devices. The blue shifted band gap energy of the fabricated Fe:ZnSe nanocrystals in comparison to the corresponding bulk value derives from size quantization characteristics of the resulting products in nanoparticle form. The exhibited quantum confinement effects were probed within the framework of the effective mass approximation model. Furthermore, the underlying mechanisms were also elucidated. This work provides a more promising synthetic strategy with advantages of being simplicity and low cost in preparation, environmentally friendly and suitable for large scale production of functionalized doped and alloyed nanocrystals with excellent synthetic reproducibility. [ABSTRACT FROM AUTHOR]

Highlights: [•] We report a facile, cost-effective, and green method to synthesize Fe:ZnSe nanocrystals. [•] The band gap of these nanocrystals can be tuned in the broad range by changing the reaction time. [•] The synthetic method provides a new band gap engineering scheme for doped semiconductor nanocrystals. [ABSTRACT FROM AUTHOR]

During the installation of deep-water drilling risers, the axial vibration caused by the heaving of drilling ships affects the safety and reliability of the operation. Conventional vibration analysis techniques consider the damping generated by the drag force to be uniformly distributed along with the risers, resulting in not real solutions. In this paper, an axial dynamics model of the drilling risers under the top excitation conditions is established, where the riser system is regarded as the assembly of an elastic rod and a block mass. Meanwhile, this model replaces the uniform damping with nonlinear distributed damping and considers the nonlinear concentrated damping of the block mass, which can be solved by the variable separation method and the iterative method. Consequently, the stress and displacement in the riser given by the present model are larger than that predicted by the model considering uniform damping or no damping. In addition, the sensitivity analysis of some parameters like the damping coefficient, the excitation amplitude and frequency, the lifting water depth, and the quality of the block mass was carried out. It shows that the stress in the top is the largest when the riser is lowered regardless of its self-weight, and it decreases almost linearly with the increase of water depth; the axial displacement increases with the increase of the block mass and the lowering water depth but reduces with the increase of the dimensionless damping coefficient. Moreover, excessive excitation frequency will increase the equivalent damping, resulting in greater stress. • A theoretical model consiering the nonlinear distributed damping and concentrated damping is established. • Linearization technique allows the equivalent damping coefficient to be iteratively solved in the frequency domain. • Some suggestions about operation for drilling risers' installation are presented by sensitivity analysis. [ABSTRACT FROM AUTHOR]

Polymethyltriethoxysilane-polymethylhydrosiloxane superhydrophobic coatings were fabricated on glass substrates by spraying technology, where the precursor mixtures contained polymethyltriethoxysilane nanoparticles obtained by the sol-gel method, and its surface was modified by polymethylhydrosiloxan (PMHS). The structure, morphologies, and hydrophobic properties of the superhydrophobic coatings were investigated by the infrared spectrometer, scanning electron microscope, and water contact angle measurement. Moreover, the effects of component ratio, solvent amount, and reaction time on the coating hydrophobic properties were investigated. 1:1.2 of component ratio, 60 mL of solvent, and 8 h of reaction time were the optimal experimental parameters, and the water contact angle of this coating was about 153°. Meanwhile, polymethyltriethoxysilane-polymethylhydrosiloxane coating showed good thermal stability and self-cleaning property. The excellent superhydrophobicity of the coating might result from the micro-nano rough structure. The results presented in this work might provide a simple, low-cost, and environmentally-friendly approach for application in the fields of anti-sticking, anticontamination, and self-cleaning to anti-corrosion. [ABSTRACT FROM AUTHOR]

In this work, we successfully prepared epitaxial La 1-x Y x CoO 3 (x = 0, 0.05, 0.1, 0.15) films on (100) SrTiO 3 by polymer assisted deposition. The synergistic effect of biaxially tensile strain and doping yttrium on the structural distortion and photoconductive process of the films has been investigated. Due to lattice mismatch, the epitaxial strain along c -axis as well as the strain-induced tetragonal distortion of La 1-x Y x CoO 3 films increase with the content of doping yttrium. As-prepared films have higher degree of CoO 6 octahedral distortion, i.e., Jahn-Teller-like tetragonal distortion, which result in lower crystal field splitting energy and narrower band gap energy, thereby elevating the charge transition. Additionally, increase of epitaxial strain leads to lower adsorption free energy in La 1-x Y x CoO 3 films, and results in the increase of chemisorbed oxygen, which is beneficial to electron transport in the process of light response. The introduction of new oxygen vacancy defect sites by doping Y3+ ions and the proper amount of oxygen vacancy can effectively inhibit the recombination of the photo-induced electron-hole pairs, thus improving the activity for photoconductive response. The results reveal that the photoconductive properties of the as-prepared films are largely related to the synergistic effect of biaxially tensile-strained tetragonal distortion of CoO 6 and doping yttrium. [ABSTRACT FROM AUTHOR]